package main

import "fmt"

func main() {
	m := make(map[int]map[int]string)
	fmt.Println(m)
	m[1] = make(map[int]string)
	m[1][1] = "OK"
	a := m[1][1]
	fmt.Println(a)

	//第二个返回值代表该键值对是否存在
	b, ok := m[2][1]
	fmt.Println(b, ok)
}